Smoking-Related Interstitial Lung Disease

Background: Smoking-related interstitial lung diseases (SR-ILDs) are a heterogeneous group of diseases with major clinical significance. Reliable epidemiological data are not yet available. Method: Review of pertinent literature retrieved by a selective search in PubMed. Results: The available data on many aspects of SR-ILDs are sparse, but recent studies on the pathophysiology and targeted treatment of these conditions have revealed ways in which clinical outcomes can be improved. High-resolution computerized tomography should be used for differential diagnosis; lung biopsy is often unnecessary. Oncogenic mutations play a role in the pathogenesis of pulmonary Langerhans-cell histiocytosis (PLCH). In the future, cladribine and vemurafenib may be treatment options for PLCH. Desquamative interstitial pneumonia (DIP) may be difficult to distinguish from respiratory-bronchiolitis- associated interstitial lung disease (RB-ILD); DIP is treated with steroids and sometimes with immune suppressants. In idiopathic pulmonary fibrosis (IPF), the antifibrotic drugs pirfenidone and nintedanib can delay disease progression. Smoking is also a risk factor for combined pulmonary fibrosis and emphysema (CPFE), rheumatoid-arthritis-associated interstitial lung disease (RA-ILD), pulmonary alveolar proteinosis (PAP), acute eosinophilic pneumonia (AEP), and diffuse alveolar hemorrhage (DAH) in Goodpasture syndrome. Conclusion: In smokers with exertional dyspnea and/or a nonproductive cough, SR-ILDs must be considered in the differential diagnosis. If an SR-ILD is suspected, the patient should be referred to a pulmonary specialist. Early treatment and smoking cessation can improve clinical outcomes, particularly in the acute and chronically progressive types of SR-ILD.